​BESS capacity in ERCOT reached 16.5 GW and 28.8 GWh to end Q2 2026. An additional 1.5 GW of new capacity came online during the quarter. In summary, total installed capacity is still growing quickly, but the pace is slowing down.

​For years, installed BESS in ERCOT roughly doubled annually. Year-over-year growth held near 100% through 2024, then eased to 76% in 2025. In 2026, it is on track for about 40%. For the first time, annual additions look set to match the prior year rather than beat it.

​​That is still a lot of new capacity, but does indicate that things have changed for BESS developers in ERCOT.

And the deceleration in newly commissioned projects does not stand alone. The interconnection queue is contracting, fewer projects are entering, and BESS revenues have remained low, pacing for $29/kW-year through the first five months of 2026. Development responds to market conditions with a long lag, and that lag appears to have turned.

​Key takeaways

• ​BESS capacity in ERCOT reached 16.5 GW and 28.8 GWh by the end of June 2026. Growth is slowing: the fleet roughly doubled each year through 2024, but is on track to grow about 40% in 2026, with additions set to match 2025 rather than beat it.
• The North load zone now holds the most BESS capacity, at 4.9 GW, having overtaken West. South follows closely at 4.6 GW.
• The one-hour era is over. Almost all of Q2's 1.5 GW came in at two hours or longer, with only 0.02 GW under 1.5 hours. San Antonio brought the first systems at four hours or longer, Padua 2 and Ferdinand.New projects are entering more slowly.
• Capacity entering the queue has halved to about 14 GW per half-year, down from a 31 GW peak in the first half of 2025.
• At the same time, more projects are dropping out. A record 13.7 GW withdrew in the first half of 2026, and cancellations after an interconnection agreement, the highest-signal exits, are accelerating.
• Projects that survive are taking longer to build. The median time from queue entry to operation has risen from 2.3 years in 2021 to 4.4 years in 2026, a sign that developers are taking longer to secure financing and may be pacing projects until revenues recover.

The pace of new BESS buildout in ERCOT is no longer accelerating

​The 1.5 GW deployed in Q2 lifted the 2026 total to 2.6 GW across the first half.

Buildout has historically been back-loaded within a given calendar year, with the second half carrying 65 to 76% of annual additions from 2023 to 2025. However, even after accounting for that, 2026 is on pace for between 5.5 to 6 GW. That would roughly match 2025's 6.0 GW, rather than beat it.

Every prior year set a record for newly installed grid-scale BESS capacity, and in most cases resulted in a year-on-year doubling. This one will not.​

In total, twenty projects reached commercial operation in Q2, and they split cleanly by size. Eight sites above 100 MW supplied 1.4 GW of the 1.5 GW total. Six topped 150 MW: Wizard, Castor, Desna, Ferdinand, Padua 2, and Pine Forest. Carambola and Radian, a two-unit site, round out that group.

The other twelve projects were all sub-10 MW batteries, adding just 0.1 GW between them. Almost nothing landed in the middle. New BESS in ERCOT is increasingly one of two things: utility-scale sites above 100 MW, or small 9.9 MW batteries often known as ‘Texas 10s’.

​The map below shows every operational site, and toggles to the full list of Q2 additions.

​Ask Ko, free

Ko is Modo Energy's AI analyst, and anyone can try it free.

Ko is strong at named-battery and portfolio questions across ERCOT… Try prompts like:

• Rank ERCOT BESS owners by operational capacity, and show how much each added in the first half of 2026
• Break down ERCOT's operational battery fleet by duration, from one-hour systems to four hours and longer
• Which load zone holds the most BESS capacity, and what are the largest operational sites in each?
• Which ERCOT batteries earned the most revenue per MW over the past year, and who owns and operates them?

It also reads Modo Energy's research library to surface adjacent context on revenues, forecasts, and market design, and it can help interpret the takeaways here.

BESS development has shifted from West to North

​For years, West Texas held the most BESS capacity, built alongside the region's wind and solar. That has changed. Load Zone North now leads at 4.9 GW, with South close behind at 4.6 GW. West sits at 4.0 GW, and Houston at 2.9 GW.

​For years, West Texas held the most BESS capacity, built alongside the region's wind and solar. That has changed. The North zone now leads at 4.9 GW, with South close behind at 4.6 GW. West sits at 4.0 GW, and Houston at 2.9 GW.